I don't think so, but I haven't looked it up for a few weeks. There are two sorts of hearth needed for any fire...."constructional" and "forgotten the damn word"
. The size of each of them depends on a variety of factors, and is different for free-standing burners compared with ones in a fireplace. I think the upper hearth, the superficial one which I've forgotten the name of, is there to keep any floor covering safe from rolling embers or suchlike (they assume that the door isn't there). I guess the reasoning is that if there is a foot of solid hearth in front of the fire and standing proud of the floor then it would be impossible for someone to come along later and lay a carpet or timber floor within the danger zone. If left as per the photo, the next owner could easily carpet right up to within say 5 or 6 inches of the front of the fire. The constructional hearth is much bigger, being basically a zone of solid floor around the fire with no flammable materials, but it doesn't have to be visually demarcated.
The other measurements to check with this fire is that it stands 6 inches clear of all the walls forming the fireplace. It looks as though it probably does.......just.